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Proceedings Paper

Measuring reality, solving the slope dilemma, and redefining the particle size distribution model
Author(s): Kerri J. Wilkerson; Philip G. Magallanes; Jonathan P. Elders; Ronald V. Peterson
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Paper Abstract

In contamination control technology relatively dirty surfaces cannot be specified with the same defining equations as those for "clean" surfaces. The current practices in the aerospace community disregard this inaccuracy in defining and specifying gradations of surface cleanliness. Using a 0.926 slope with an IEST-STD-CC1246D particle distribution to describe cleanliness on dirty surfaces, or surfaces subjected to fallout, is inaccurate, unrealistic, misleading, and often impossible to verify. Most importantly, using this model provides incorrect information to experts who calculate sensor performance: a slope of 0.926 is appropriate only for cleaned surfaces. However, the industry continues to use the same slope to describe all surfaces, clean or dirty. Current measurements taken from Raytheon labs have shown that particle distributions dominated by fallout typically have a slope between 0.3 and 0.5, in concurrence with previous studies. Based on the accumulated data, the authors propose that particle distributions for dirty surfaces be described by a second model, which should be incorporated into the next revision of IEST-STD-CC1246.

Paper Details

Date Published: 7 September 2006
PDF: 11 pages
Proc. SPIE 6291, Optical Systems Degradation, Contamination, and Stray Light: Effects, Measurements, and Control II, 62910I (7 September 2006); doi: 10.1117/12.695250
Show Author Affiliations
Kerri J. Wilkerson, Raytheon Space and Airborne Systems (United States)
Philip G. Magallanes, Consultant (United States)
Jonathan P. Elders, Raytheon Space and Airborne Systems (United States)
Ronald V. Peterson, Consultant (United States)

Published in SPIE Proceedings Vol. 6291:
Optical Systems Degradation, Contamination, and Stray Light: Effects, Measurements, and Control II
O. Manuel Uy; John C. Fleming; Michael G. Dittman, Editor(s)

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